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[PATCHES] Kexec syscall support, boots kernels from SD or USB (11/6/11, GB support)

11/6/11 Update: Added statically-linked kexec to kexec_patches.tar.gz and example update.zips. Now works in stock recovery and CM7 CWM (with a kexec-patched kernel).
10/19/11 Update: Added patches for the recently released GB sources to kexec_patches.tar.gz.
Attached is a set of patches (kexec_patches.tar.gz) against EC05, and the recently released GB sources, to implement kexec syscall support in the Epic's kernel. kexec enables the booting of kernels "directly" from the SD card or over USB without having to flash them to the device first. This allows us to easily use, test, and switch between many kernels, not just the one (two with recovery) there's room for on flash.
When used in conjuction with modified init.rc scripts, this allows entire ROMs (with their own kernels) to run from SD card. In short, this allows us to run custom-kernel ROMs (e.g,. CyanogenMod) alongside each other or a stock kernel without having to flash back and forth.
Also attached is a modified version of the kexec userspace tool (also in kexec_patches.tar.gz, along with source and patches) that facilitates the proces of loading and kexecing a kernel image. Finally, attached is a demo EC05 kernel with kexec enabled (demo_kernel.tar.gz; mostly stock: RFS support only, testkeys recovery w/adbd, but does inlcude the keyboard patches), example update.zips that kexec an SD-card kernel from recovery--either as a normal boot (boot_zImage.zip) or recovery boot (boot_zImage_recovery.zip), and a script (patch_decomp_cachebufram.sh) to binary patch unmodified kernels to kexec boot faster.
Note, this thread is primarilly intended for kernel developers. Kexec probably won't be of great utility to end users until commonly-used kernels are patched. Also, although stock kernels can be kexec'd, they need some init.rc modifications boot an entire ROM from SD card. Hopefully the fine folks here will come up with a user-friendly implementation of this work that's easy for everyone to use.
Instructions:
Flash a kexec-enabled kernel (e.g., the attached demo kernel) to either /dev/block/bml7 or /dev/block/bml8. For testing purposes, this kernel needs either "ro.secure=0" or "ro.debuggable=1" set in default.prop, and also needs recovery.rc/fota.rc modified to spawn the adbd service, so that an adb root shell is available while in recovery. Also copy the attached kexec tool to a convenient location on the device (e.g., /data/local/tmp/kexec).
Reboot into recovery. If the kexec kernel is installed to bml7, run "adb reboot recovery" while the phone is running. If installed to bml8, power down and boot into recovery by holding the volume-down, camera, and power buttons.
Make sure adb is running as root. If it's not, try running "adb root".
Find the kernel (zImage) you wish to boot. These can be extracted from a kernel update.zip or Odin .tar file, or use the demo kernel again.
Push the zImage into RAM (tmpfs) with:
Code:
adb push zImage /tmp
Now, open an adb root shell with "adb shell" and run the commands:
Code:
mount -ro remount /dev/block/stl6 /mnt/.lfs
mount -ro remount /dev/block/stl9 /system
mount -ro remount /dev/block/stl10 /data
mount -ro remount /dev/block/stl11 /cache
/data/local/tmp/kexec --load-hardboot --mem-min=0x50000000 --append="console=ttySAC2,115200 loglevel=4" /tmp/zImage
sync
/data/local/tmp/kexec -e
after which the phone will reboot, show the SAMSUNG logo, and eventually boot the kexec'd kernel. Do note that when booting unmodified kernels (see below), the SAMSUNG logo will persist for ~30 seconds longer than usual.
Also note that kexec performs an "abrupt" reboot, i.e., it doesn't shutdown the system normally. Hence it's important to kexec from recovery where few services are running. It's also prudent to remount file systems read-only and sync them to avoid any potential (although unlikely) of corruption.
In the future, kexec could be better integrated into the Android framework to allow for a clean shutdown. Otherwise, probably the best way to deploy kexec is through an update.zip file that boots a kernel from the SD card. See the attached example update.zips.
Technical details:
kexec is feature of Linux that allows it to directly execute (boot) a new kernel in place of itself, allowing Linux to effectively serve as its own bootloader.
The kexec procedure is two step. The first "kexec" command loads a zImage from disk, constructs parameters (e.g., the kernel command line), and stages it in memory, after which Linux continues to run as normal. The second "kexec" command tells Linux to execute (boot) the staged kernel.
In the standard implementation, Linux "soft boots" kexec'd kernels. That is, on "kexec -e" the running instance of Linux shuts-down all devices, drivers, and goes through the process of unloading itself as it does during a normal reboot. However, instead of invoking a hardware reboot, Linux, at the final stage of unloading itself, jumps to start executing the new kernel.
This soft boot process requires that Linux hardware drivers are fully capable of unloading, reloading, and reinitializing the associated hardware without hardware-reboot or bootloader assistance. Since, for many built-in drivers, this capability is only used by kexec, hardware is often left in an unexpected or unknown state on unload, and thus the kexec'd kernel hangs on boot. Unfortunately this is the case with the Epic kernel, and soft booting doesn't work.
To work around this, the attached patches implement a "hard boot" method for kexecing kernels. Here, we use kexec to stage a kernel in memory as usual. On "kexec -e", Linux shuts-down as before, and at the very end of the unloading process it does two things: (i) scribble some information on how to boot the kexec'd kernel to a "special place" in memory, and (ii) performs a hardware reboot, invoking the Epic bootloader as a normal reboot does.
On reboot, the bootloader loads the (previously-running) bml7 or bml8 kernel and starts executing it. Here, the hardboot patch modifies the Linux the zImage decompressor code to check the "special place" in memory to see if we're actually kexecing a different kernel. If so, it switches over to the other kernel, already staged elsewhere in memory.
Known Issues:
Kernel Command Line:
Kexec (via hardboot) can boot stock or non-kexec-modified custom kernels. However, unless the copy_atags patch is applied, they can only use the kernel command line provided by the bootloader, as opposed to the custom command line provided by kexec. Although this isn't a problem when kexecing from a bml7 boot kernel, kexecing from a bml8 kernel runs recovery (fota.rc) instead of a normal boot (init.rc).
With the copy_atags patch, the command line for the kexec'd kernel must be provided by with kexec's --append option. These are the command lines provided by the bootloader in normal boot and recovery scenarios, any of which may be used:
Code:
Normal boot (init.rc):
console=ttySAC2,115200 loglevel=4
"adb reboot recovery" (recovery.rc):
bootmode=2 console=ttySAC2,115200 loglevel=4
Three-finger recovery boot (fota.rc):
bootmode=3 console=ttySAC2,115200 loglevel=4
Slow Booting:
Kexec booting of a stock or non-kexec-modified custom kernel is known take significantly longer than a regular boot, sitting at the SAMSUNG logo for 35 seconds instead of 8. The decomp_cachebufram patch resolves this issue for modified kernels. In addition, the attached patch_decomp_cachebufram.sh script will binary patch the decompressor code for any (to my knowledge) Epic kernel.
Many more details on the patches themselves are in the accompanying READMEs.
Mirror links:
Kernel & kexec-tools patches: kexec_patches.tar.gz
Kexec EC05 demonstration kernel: demo_kernel.tar.gz
Recovery script to boot /sdcard/zImage (normal boot): boot_zImage.zip
Recovery script to boot /sdcard/zImage (recovery boot): boot_zImage_recovery.zip
Script to binary patch decompressor code: patch_decomp_cachebufram.sh

Is this different in function than rodderik's dual boot support?
I know his didn't include usb booting support, but sdcard booting appears to be the same...although this seems a little cleaner, possibly
Sent from my SPH-D700 using xda premium

squshy 7 said:
Is this different in function than rodderik's dual boot support?
I know his didn't include usb booting support, but sdcard booting appears to be the same...although this seems a little cleaner, possibly
Sent from my SPH-D700 using xda premium
Click to expand...
Click to collapse
His uses a modified init, which then choses to load which init.rc, the one names init.rc.sdcard or normal init.rc. This (kexec method) reminds me A LOT like how they ran linux/android on winmo devices...it shuts down android and then runs the kernel they want (if I read correctly).

squshy 7 said:
Is this different in function than rodderik's dual boot support?
I know his didn't include usb booting support, but sdcard booting appears to be the same...although this seems a little cleaner, possibly
Sent from my SPH-D700 using xda premium
Click to expand...
Click to collapse
Yes. The genocide implementation allows a ROM to boot from the sd card as long as the kernel on the main ROM supports the sd ROM. this means you cannot dual boot a gingerbread and a froyo ROM because the need different kernels .
With this patch that limitation is removed as the sd based ROM can use its own separate kernel. This you may run stock ec05 and keep cyanogen or a gingerbread on the sd card to test and play with.
Great work mkasick
Sent from my SPH-D700 using Tapatalk

I was never interested in the dual boot feature since that was ROM's only and itwas limited by kernel support.
But now this really interest me, can't wait till we see some developers take advantage of this.
Sent from my SPH-D700 using xda premium

All I have to say is hope you stick with the epic your amazing
Sent from my SPH-D700 using Tapatalk

Yes, this is complementary to Rodderik's dual boot. Kexec allows one to load a different kernel, but it still defaults to booting the ROM stored in flash. Which is great for kernel testing, but not of much use otherwise.
It's easy enough to modify a kernel to load a ROM only from SD, but then we'll start seeing a divide between "bml kernels" and "SD kernels", when really it'd be nice to have init scripts that support both. That's where Rodderik's work comes in.
Probably the best is to have a kernel command line parameter that specifies where the ROM is located, so it can be passed in. Something like "console=ttySAC2,115200 loglevel=4 systemfs=mmcblk0p2 datafs=mmcblk0p3 cachefs=mmcblk0p4". These would default to stl9, stl10, stl11 respectively if unspecified. The kernel command line is available to init through "/proc/cmdline", and it's easy enough to parse in a shell script.
But yes, keeping a working ROM on flash while testing/debugging CyanogenMod was my primary motivation, since I need a working phone "during the day" and can't touch CyanogenMod otherwise.
formula84 said:
All I have to say is hope you stick with the epic your amazing
Click to expand...
Click to collapse
Thanks!
I'm much of a year out on a full upgrade, and I'm not considering a new device sooner as long as my Epic still works.
Edit: An obvoius limitation is modem compatibility. I've avoided the GB leaks thus far, so I'm not sure what's the status with that. But if GB supports the EC05 modem, then you can dual boot EC05 and GB-whatever. Same if EC05 supports newer modems.
Speaking of which, anyone know what GB modem compatibilty is like?

mkasick said:
Yes, this is complementary to Rodderik's dual boot. Kexec allows one to load a different kernel, but it still defaults to booting the ROM stored in flash. Which is great for kernel testing, but not of much use otherwise.
It's easy enough to modify a kernel to load a ROM only from SD, but then we'll start seeing a divide between "bml kernels" and "SD kernels", when really it'd be nice to have init scripts that support both. That's where Rodderik's work comes in.
Probably the best is to have a kernel command line parameter that specifies where the ROM is located, so it can be passed in. Something like "console=ttySAC2,115200 loglevel=4 systemfs=mmcblk0p2 datafs=mmcblk0p3 cachefs=mmcblk0p4". These would default to stl9, stl10, stl11 respectively if unspecified. The kernel command line is available to init through "/proc/cmdline", and it's easy enough to parse in a shell script.
But yes, keeping a working ROM on flash while testing/debugging CyanogenMod was my primary motivation, since I need a working phone "during the day" and can't touch CyanogenMod otherwise.
Thanks!
I'm much of a year out on a full upgrade, and I'm not considering a new device sooner as long as my Epic still works.
Edit: An obvoius limitation is modem compatibility. I've avoided the GB leaks thus far, so I'm not sure what's the status with that. But if GB supports the EC05 modem, then you can dual boot EC05 and GB-whatever. Same if EC05 supports newer modems.
Speaking of which, anyone know what GB modem compatibilty is like?
Click to expand...
Click to collapse
As far as I know, and from experience, modems are a free for all except for bonsai. Ec05 modem works on gb, leaked modems work on ec05.

this is definitely very cool, thanks mkasick!
Sent from my SPH-D700 using XDA Premium App

mkasick you never cease to amaze me...i'll definately play with this, this week if i have the time!

Rodderik said:
mkasick you never cease to amaze me...i'll definately play with this, this week if i have the time!
Click to expand...
Click to collapse
Great!
If you run into something not particularly straight forward, or think there's something I can clarify, please ask. I've been playing around with this long enough that I fear I might've overlooked documenting a detail or two that would be helpful for others.

So to patch any kernel u just point the script to the zImage?
sent from my epic 4g. with the key skips.

ugothakd said:
So to patch any kernel u just point the script to the zImage?
Click to expand...
Click to collapse
The script only implements one patch, it allows any kernel to boot ~30 seconds faster when kexec'd.
But yes, "./patch_decomp_cachebufram.sh zImage" modifies that zImage to boot faster. It requires the xxd hexdump tool that's packaged with vim.
Kexec support itself, along with the slew of other source patches, has to be applied to a kernel source tree, from which a new kernel must be built to take advantage of them.

mkasick said:
The script only implements one patch, it allows any kernel to boot ~30 seconds faster when kexec'd.
But yes, "./patch_decomp_cachebufram.sh zImage" modifies that zImage to boot faster. It requires the xxd hexdump tool that's packaged with vim.
Kexec support itself, along with the slew of other source patches, has to be applied to a kernel source tree, from which a new kernel must be built to take advantage of them.
Click to expand...
Click to collapse
I see...so its a no-go for gb. Or at least quick gingerbread.
sent from my epic 4g. with the key skips.

ugothakd said:
I see...so its a no-go for gb. Or at least quick gingerbread.
Click to expand...
Click to collapse
You should be able to kexec a GB kernel, but you'd need an EC05-ish /system on flash to boot recovery. Unless GB recovery is compatible with Froyo kernels.
If you're going to boot a GB kernel, you'd probably want to repackage the initramfs with an init.rc that loads the rest of the GB ROM off SD. It's actually not a bad way to keep EC05 around for a stable, working phone, and to test GB leaks as they happen. Which, hopefully, shouldn't be much longer.

wow mkasick, you never cease to amaze me bro...
I wish I wasn't working so many damned hours now, with your patches, I really want the dual boot now. Like you, the need for a working phone at all times is what keeps me from flashing more ROMs, including EpicCM and the gb leaks...
I hope Rodderik figures this out pretty quickly, as most of my dev time is spent on the IRC channels, and he's usually around to help and answer questions.
Once I can get my Clean Kernel working with this, I'll be stoked... I have had a tough time dealing with patches thus far, I usually git cherry-pick and/or manually edit, so I need to figure out how to use the patches correctly.
Anyways, gotta go to work now (I'm working 50+ hour weeks now, hence the time constraints), but hopefully I can get the time to get it into my kernel.
Thanks, mkasick!
Sent from my Samsung Epic4G

DRockstar said:
I have had a tough time dealing with patches thus far, I usually git cherry-pick and/or manually edit, so I need to figure out how to use the patches correctly.
Click to expand...
Click to collapse
What environment (OS, etc.) are you using? Is the "patch" utility working for you?
The patches are split up based on functionality. In each patch directory there's a "series" file that lists the order they should be applied. There's a program, quilt that can help manage them but it's not necessary. If you're running a bourne shell (e.g., bash) in the "Kernel" directory of the kernel sources, you should be able to apply the patches with:
Code:
while read i; do patch -p 1 < "/path/to/kexec_patches/kernel-EC05/$i"; done < "/path/to/kexec_patches/kernel-EC05/series"
Whether they'll apply cleanly or not is a different story, but that's the general idea.
And yeah, time ....

Thank you mkasick, that's a great explanation, I think I can handle that, much appreciated!
For the record, I compile by ssh into dev boxes donated for dev use. They all run linux in different distros. I find this most convenient since I can do most everything from the command line using your brilliant connectbot for epic
Sent from my Samsung Epic4G

With those recovery scripts, doesn't Clockwork Mod have to have kexec set up?

ugothakd said:
With those recovery scripts, doesn't Clockwork Mod have to have kexec set up?
Click to expand...
Click to collapse
You mean for boot_zImage_recovery.zip to work?
The CWM kernel doesn't need full kexec support in order to be booted via kexec. But it does need the copy_atags patch in order to respect the "bootmode=3" kernel argument.
Actually, you can take any existing Epic kernel and somewhat-easily fix it to be bootable via kexec. Steps are:
1. Extract EC05 kernel sources. Or use the GB sources, it doesn't matter, it doesn't even have to match the version of the kernel you're fixing.
2. Apply "decomp_cachebufram" and "decomp_copy_atags" patches.
3. Build a kernel. Config options don't matter much since this kernel is going to be thrown away.
4. Find the zImage for the kernel you want to fix. Run:
Code:
skip=`grep -Fabom 1 $'\x1f\x8b\x08' zImage | head -n 1 | cut -d : -f 1`
dd if=zImage bs=1 skip="$skip" | gunzip > Image
cp Image arch/arm/boot/Image
which extracts the decompressed kernel payload from the zImage, and replaces the "Image" that was previously built with the one you've extracted.
5. Run "make" in the kernel source directory again. You might have to append a "CROSS_COMPILE=" path to match the one used in a build script. The output should be:
Code:
CHK include/linux/version.h
make[1]: `include/asm-arm/mach-types.h' is up to date.
CHK include/linux/utsrelease.h
SYMLINK include/asm -> include/asm-arm
CALL scripts/checksyscalls.sh
CHK include/linux/compile.h
Kernel: arch/arm/boot/Image is ready
GZIP arch/arm/boot/compressed/piggy.gz
AS arch/arm/boot/compressed/piggy.o
LD arch/arm/boot/compressed/vmlinux
OBJCOPY arch/arm/boot/zImage
Kernel: arch/arm/boot/zImage is ready
Building modules, stage 2.
MODPOST 13 modules
which shows that the build process took the existing, extracted Image, compressed it, and attached a new kexec-compatible decompressor to it.
The resulting "arch/arm/boot/zImage" can be kexec'd, and command line arguments should be respected, e.g., if you want to boot into CWM recovery.

[HowTo] Compile the Kernel Source Code for the HTC One XL

Hi guys!
Someone requested a tutorial on how to build the kernel source code, so I thought I might as well do it I'll give you a bit more information too.
Maybe this will kick start kernel development a little bit too. Who knows.
Anyway:
1. Set up your build environment as per this guide by AOSP here: http://source.android.com/source/initializing.html
This guide will be primarily aimed at Ubuntu, but it should be easy enough to do on other Linux PCs. Ubuntu is highly recommended. And don't ask about Windows.
2. Download the toolchains: http://code.google.com/p/rohan-kernel-evita/downloads/detail?name=toolchains.tar.gz&can=2
I've hosted both GCC 4.4 and GCC 4.6 (prebuilt) on my Google Code page. These are for Linux.
Download the toolchain package here: http://code.google.com/p/rohan-kernel-evita/downloads/detail?name=toolchains.tar.gz&can=2
Then un-tar the archive and extract it to your home folder so that the path to the toolchain directories are ~/toolchain/whatever-one-you-want
3. At this point you can decide which kernel source you want to download. There are really two sources.
The first choice is getting it from HTC Dev directly. This is good if you want to build your kernel for a Sense 4 ICS ROM. If you want to build for AOSP/JB, then scroll down below all the following HTC stuff.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
To use HTC's source:
Go to HTCdev.com and make an account. Then download the source code for our device (I'd recommend the "One X" source under carrier "AT&T" version "2.20". Let the zip file download and extract it to your home folder (so the path is /home/user/evita-ics..../
To build HTC's source, run these commands:
Code:
cd ~/evita-ics-whatever_the_directory_is_named
export ARCH=arm
make elite_defconfig
Second command is saying what type of architecture we want (we are compiling for ARM processors, so we want ARM)
Third command is saying to make the default config for our device (whose hardware is codenamed "elite")
Then to build the actual kernel:
Code:
make -j# ARCH=arm CROSS_COMPILE=~/toolchain/arm-eabi-4.4.3/bin/arm-eabi-
In the command above, there is "-j#". Replace the "#" with the number of CPUs you have.
Ask me about it if you need help. That should be it! Let the build go and in a few minutes you should have a zImage file located at ~/evita-ics-..../arch/arm/boot. That is the actual kernel.
To test out the zImage (kernel), connect your device via fastboot mode and type:
Code:
fastboot boot /path/to/zImage
Combined with the ramdisk, thats what makes the boot.img file. Eventually if you want to distribute your kernel, you should use an installer that injects the zImage into the boot.img or combine the zImage with a ramdisk to make a boot.img. I can do a tutorial on that later on as well.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
To get the "other" source:
This source is based off of HTC's source and includes other devices as well in it (the One S and Evo 4G LTE). Its good if you want to build JB AOSP kernels.
To download this kernel source do this:
Code:
mkdir ~/kernel
cd ~/kernel
git clone https://github.com/CyanogenMod/android_kernel_htc_msm8960.git -b android-msm-evita-3.0
This version also includes a number of optimizations and odd bug fixes present in the HTC version.
To build this second source, run these commands:
Code:
cd ~/kernel/android_kernel_htc_msm8960
export ARCH=arm
make elite_defconfig
Second command is saying what type of architecture we want (we are compiling for ARM processors, so we want ARM)
Third command is saying to make the default config for our device (whose hardware is codenamed "elite")
Then to build the actual kernel:
Code:
make -j# ARCH=arm CROSS_COMPILE=~/toolchain/arm-linux-androideabi-4.6/bin/arm-eabi-
In the command above, there is "-j#". Replace the "#" with the number of CPUs you have.
Ask me about it if you need help. That should be it! Let the build go and in a few minutes you should have a zImage file located at ~/evita-ics-..../arch/arm/boot. That is the actual kernel.
To test out the zImage (kernel), connect your device via fastboot mode and type:
Code:
fastboot boot /path/to/zImage
Combined with the ramdisk, thats what makes the boot.img file. Eventually if you want to distribute your kernel, you should use an installer that injects the zImage into the boot.img or combine the zImage with a ramdisk to make a boot.img. I can do a tutorial on that later on as well.
-----------------------------------------------------------------------------
The second option is also a bit better as it uses the 4.6 toolchain instead of GCC 4.4. HTC's source doesn't work with GCC 4.6 so it can't be used without changes that the second source has.
If you have any questions, feel free to post here, message me on twitter (@rohanXm), chat me on IRC (#HTC-One-XL) or PM me!
If this helped you, please consider hitting the donation link under my username on the left. Donations are never required but always appreciated.

Instead of downloading cm10 the readme inclided with the HTC source has directions for getting a tool chain which will compile the source.
Sent from my HTC One X using Tapatalk 2

Perfect. Now I just have to read.
Sent from my HTC One XL bumping it

rohan32 said:
Code:
repo init -u git://github.com/CyanogenMod/android.git -b jb
Click to expand...
Click to collapse
FYI, It looks like the branch name has changed. When I changed "jb" to "jellybean" the repo init command worked.

Rohan. You are one bad MF'er
Sent from my twin turbo'ed OneXL rocking rezound beats

rohan32 said:
2. You can either try to find a standalone package of the precompiled toolchain, or you are going to need to download a ROMs source. I'd recommend downloading a ROMs source since I've never found a good toolchain that worked for me. If you find one that works, post below
For now we will download CM10 since that seems like the defacto standard.
Click to expand...
Click to collapse
I downloaded the 2.20.502.7 kernel source and when I extracted it there was a file named evita_readme.txt which gave another, possibly more "official", location for downloading a toolchain:
--Please follow below command to download the official android toolchain: (arm-eabi-4.4.3)
git clone https://android.googlesource.com/platform/prebuilt
Click to expand...
Click to collapse
I just performed a build with this toolchain but got this error when I attempted to load zImage via fastboot:
c:\>fastboot flash boot zImage
sending 'boot' (5140 KB)...
OKAY [ 1.044s]
writing 'boot'...
FAILED (remote: image error! (BootMagic check fail))
finished. total time: 1.077s
Click to expand...
Click to collapse
I'm not sure if this is caused by the toolchain or if I screwed something up. Have you ever seen this error before?
EDIT: Ok I see what I did incorrectly. The zImage needs to be "Combined with the ramdisk". You wouldn't know how to perform this operation... would you?

denversc said:
I downloaded the 2.20.502.7 kernel source and when I extracted it there was a file named evita_readme.txt which gave another, possibly more "official", location for downloading a toolchain:
I just performed a build with this toolchain but got this error when I attempted to load zImage via fastboot:
I'm not sure if this is caused by the toolchain or if I screwed something up. Have you ever seen this error before?
EDIT: Ok I see what I did incorrectly. The zImage needs to be "Combined with the ramdisk". You wouldn't know how to perform this operation... would you?
Click to expand...
Click to collapse
You are trying to flash a zImage
To my knowledge, only booting zImages work on this device. For the time being just boot the zImage (use fastboot boot zImage)
I will make a tutorial on how to combine the zImage created with a ramdisk to make a boot.img when I get the chance

denversc said:
FYI, It looks like the branch name has changed. When I changed "jb" to "jellybean" the repo init command worked.
Click to expand...
Click to collapse
Oops, my bad! That was a mistake. AOKP uses -jb and CM uses -jellybean so I got them switched fixed now

Out of any device I've seen more people actually interested in helping and learning to help then any other community. I've watched noobs become less noobish.. I've watched skizz learn how to make themes. Hell I've learned 10 fold what I knew before this phone myself.
That is beautiful, and now such an informed, helpful post such as this.
Have great Sunday you guys! I think I might give this a shot!
Sent from my One X

I'll streamline this process in a bit, so that you don't need to download CM10
Edit: cleaned up post, now I'm uploading just the toolchains. Its a tar.gz archive, around 150mb. Much better than downloading the entire CM10 source

rohan32 said:
You are trying to flash a zImage. To my knowledge, only booting zImages work on this device. For the time being just boot the zImage (use fastboot boot zImage)
Click to expand...
Click to collapse
Thanks for your response, rohan. You are absolutely right: I was incorrectly attempting to flash zImage straight to the boot partition, and the error produced by flashboot was justified. I have since successfully "tested out" my compiled zImage by flashing it via "fastboot boot zImage" and it worked like a charm! I ported the modifications from sbryan's Blackout BeastMode kernel and I am now able to OC to 2106 MHz and UC to 192 MHz. It's been running solid for the past few hours at least
Of course, the kernel reverts back to the one stored in the boot partition after a reboot, and I want my shiny new kernel to "stick". I've done a bit of research on this topic and found some information about combining my zImage with a ramdisk into a "real" boot.img but have not yet been successful in creating a boot.img which does not bootloop after flashing it.
For example, I found an article on xda called Basic Kernel Kitchen for Minor Kernel Tweaking which points to a "kitchen sink" tool for creating a boot.img from a zImage and a ramdisk. My problem is that I don't know where to get or how to make a ramdisk. So I tried using the ramdisk from the boot.img of the ROM that I am currently running (CleanROM 4.5 DE) but just got into a bootloop. I've since been doing some yard work today so haven't gotten back to investigating further.
I also found another program named abootimg which can also produce a boot.img from a zImage abd a ramdisk, but when I tried it an error message about my zImage being "too big" was produced.
If it's not obvious yet, I am kind of fumbling around in the dark as compiling and deploying custom kernels is completely new to me! But this post was the most valuable resource I've come across in getting to this point. Thanks so much for writing it! I eagerly await your next article about creating the boot.img
---------- Post added at 06:05 PM ---------- Previous post was at 05:50 PM ----------
rohan32 said:
cleaned up post
Click to expand...
Click to collapse
Thanks for cleaning up the post rohan. I have a few follow-up questions/comments:
missing toolchains link -- the post says "Download the toolchains:" but there is no link to download anything... did you forget to paste the link?
official toolchain -- That's great that you uploaded the toolschains to save tonnes of bandwidth. The CM10 source was taking a VERY long time for me to grab. However, I imagine some people (like me) would prefer to get the toolchain from an "official" source. In the "evita_readme.txt" file of the kernel sources downloaded from HTC dev it instructs one to use the official sources from "git clone https://android.googlesource.com/platform/prebuilt". This is the toolchain that I used and it successfully built the zImage.
ko files -- I noticed in the ZIP file for Blackout BeastMode, in additional to installing the zImage it also puts a bunch of "ko" (kernel modules I believe) into the /system partition (eg. qce40.ko). Should I also be deploying .ko files from my build to the device?
Thanks!

denversc said:
Thanks for your response, rohan. You are absolutely right: I was incorrectly attempting to flash zImage straight to the boot partition, and the error produced by flashboot was justified. I have since successfully "tested out" my compiled zImage by flashing it via "fastboot boot zImage" and it worked like a charm! I ported the modifications from sbryan's Blackout BeastMode kernel and I am now able to OC to 2106 MHz and UC to 192 MHz. It's been running solid for the past few hours at least
Of course, the kernel reverts back to the one stored in the boot partition after a reboot, and I want my shiny new kernel to "stick". I've done a bit of research on this topic and found some information about combining my zImage with a ramdisk into a "real" boot.img but have not yet been successful in creating a boot.img which does not bootloop after flashing it.
For example, I found an article on xda called Basic Kernel Kitchen for Minor Kernel Tweaking which points to a "kitchen sink" tool for creating a boot.img from a zImage and a ramdisk. My problem is that I don't know where to get or how to make a ramdisk. So I tried using the ramdisk from the boot.img of the ROM that I am currently running (CleanROM 4.5 DE) but just got into a bootloop. I've since been doing some yard work today so haven't gotten back to investigating further.
I also found another program named abootimg which can also produce a boot.img from a zImage abd a ramdisk, but when I tried it an error message about my zImage being "too big" was produced.
If it's not obvious yet, I am kind of fumbling around in the dark as compiling and deploying custom kernels is completely new to me! But this post was the most valuable resource I've come across in getting to this point. Thanks so much for writing it! I eagerly await your next article about creating the boot.img
---------- Post added at 06:05 PM ---------- Previous post was at 05:50 PM ----------
Thanks for cleaning up the post rohan. I have a few follow-up questions/comments:
missing toolchains link -- the post says "Download the toolchains:" but there is no link to download anything... did you forget to paste the link?
official toolchain -- That's great that you uploaded the toolschains to save tonnes of bandwidth. The CM10 source was taking a VERY long time for me to grab. However, I imagine some people (like me) would prefer to get the toolchain from an "official" source. In the "evita_readme.txt" file of the kernel sources downloaded from HTC dev it instructs one to use the official sources from "git clone https://android.googlesource.com/platform/prebuilt". This is the toolchain that I used and it successfully built the zImage.
ko files -- I noticed in the ZIP file for Blackout BeastMode, in additional to installing the zImage it also puts a bunch of "ko" (kernel modules I believe) into the /system partition (eg. qce40.ko). Should I also be deploying .ko files from my build to the device?
Thanks!
Click to expand...
Click to collapse
Hey!
Sorry, set it to upload then got distracted Link posted
The reason why your boot.imgs bootloop is because there is a special ramdisk address that needs to be set when combining the ramdisk with the zImage, and most kitchens don't support this. You also need to set the address after setting the base value.
I will post a guide on how to make it a real boot.img whenever I get the chance.

I'm telling you people, Rohan is a BOSS. Most helpful dev I know.
Sent from my HTC One XL using xda app-developers app

rohan32 said:
Hey!
Sorry, set it to upload then got distracted Link posted
The reason why your boot.imgs bootloop is because there is a special ramdisk address that needs to be set when combining the ramdisk with the zImage, and most kitchens don't support this. You also need to set the address after setting the base value.
I will post a guide on how to make it a real boot.img whenever I get the chance.
Click to expand...
Click to collapse
I have the zImage thanks to your tutorial, but I want to know how to create the kernel zip, whenever you have time will be amazing if you can post a guide, I'm really looking forward to that guide, because i haven't been able to locate a guide that works
Sent from my HTC One XL using xda premium

rohan32 said:
Hi guys!
Second command is saying what type of architecture we want (we are compiling for ARM processors, so we want ARM)
Third command is saying to make the default config for our device (whose hardware is codenamed "elite")
Then to build the actual kernel:
Code:
make -j# ARCH=arm CROSS_COMPILE=~/toolchain/arm-linux-androideabi-4.6/bin/arm-eabi-
Click to expand...
Click to collapse
This is the correct make for "other source" kernel.
Code:
make -j# ARCH=arm CROSS_COMPILE=~/toolchain/arm-linux-androideabi-4.6/bin/[COLOR="Red"]arm-linux-androideabi-[/COLOR]

Can you make a tutorial on how to insert governors into a kernel?

Compiling problem
Hey man,
Please help me I followed your article but when I try copile with:
make -j2 ARCH=arm CROSS_COMPILE=~/toolchain/arm-eabi-4.4.3/bin/arm-eabi
I got something like this:
/home/martin/toolchain/arm-eabi-4.4.3/bin/../lib/gcc/arm-eabi/4.4.3/../../../../arm-eabi/bin/as: error while loading shared libraries: libz.so.1: cannot open shared object file: No such file or directory
Thanks
UPDATE:
now its work
I went deeper and install lib32z1 with "sudo apt-get install lib32z1"... now its work

My device repositories are not available on github, But I got device tree and vendor blobs by making changes in similar device repo. That reference device's kernel's lineageos_defconfig is situated in htc msm8974 kernel repo. So how can I get lineageos_defconfig for my device, and which other my device related kernel files(.dtsi or any other) I have to push in htc msm8974 repo and get those files to make things ready for build?
Please help......

make kexec guestable kernels

hi all,
i'm going to support multiple android roms loading in my kernel_chooser + root_chooser project.
in few words it will be a powerful bootloader for android.
this is what it will be able to do ( many points are yet working ):
kernel loading thought kexec
boot from external devices
boot from subfolders
custom background
change android /sytem partition
change android /data partition
wipe android /cache partition
what i'm asking to you it's to make your android rom's kernel kexec-ready, applying them a kexec guest patch.
thus to make them ready to load for me.
if not i have to patch your kernel every time you modify it.
kernel_chooser and root_chooser are hosted here: https://github.com/tux-mind/tf201-dev
they are made for the asus transformer prime ( TF201 ), but they can run on any android device with your help.
i will add you to the github collaborators if you want to help.
now we are working on multiple android roms support.
thanks in advance for your time.
-- tux_mind

@tux_mind sounds like an interesting idea. So this works for all device's kernels? Once I apply the patch to my kernel source, what happens after that? I'll make sure to follow your progress, good work

HTCDreamOn said:
@tux_mind sounds like an interesting idea. So this works for all device's kernels? Once I apply the patch to my kernel source, what happens after that? I'll make sure to follow your progress, good work
Click to expand...
Click to collapse
thanks
yes, this should work for all devices, except for a little tuning of the partition with the configuration data ( /data ).
i have to make it to self-detect the /data partition.
let's say for example that you want to use it on your HTC Vision.
i have to build an host kernel by the stock one applying the host kexec patch.
than i have to build an android boot image which contains kernel_chooser as initrd and the above kernel.
this android boot image will be written to your current one though fastboot.
after that kernel_chooser will be able to load any kernel patched with the guest patch.
obviously the loaded kernel must be made for that device
it can also load a custom initrd and use a custom kernel CMDLINE.
so, after i made a HTC Vision kernel_chooser, your rom it's ready to load if you applied the guest patch to you kernel.
i can't explain well how to make you rom "bootable" because we are developing this
but if your kernel is kexec-loadable it will be supported by kernel_chooser.
i will update you in the next days
bye!

Really great idea! As it support other devices I can throw in my kernel which is a kexec one for the Motorola RAZR, because of our locked bootloader. The question is: how different are the methods to use kexec?
M.o.t.o.r.o.l.a.R.a.z.r - JBX-Kernel 0.5a - Tapatalk4

@tux_mind this'll sound really stupid but how do actually patch our kernels for this? Do I have to build kexec from here or something?

dtrail1 said:
how different are the methods to use kexec?
Click to expand...
Click to collapse
kexec it's a syscall, so it's the same on every arm device.
HTCDreamOn said:
@tux_mind this'll sound really stupid but how do actually patch our kernels for this? Do I have to build kexec from here or something?
Click to expand...
Click to collapse
there is a good explaination here:
http://forum.xda-developers.com/showthread.php?t=2104706
look at the "Compatibility patch".
for my tf201 the guest patch is this: http://git.lilstevie.geek.nz/?p=ubu...ch;h=54c2e480682afb0629f3854dfea4154f528421e5
which is almost the same...
i hope that almost all kernels have the same host/guest patch, in order to save us a lot of work.
the patch isn't need for kexec, but for hardboot kexec, thus to physically shutdown and restart the device with your kernel, from 0.
the standard kexec it's a assembly jump to 0 ( jmp 0x0 ) with the new kernel loaded in the .text section.
but the standard method don't reinitialize the devices and many other things that could rest in a undefined state.
btw, i have almost done my work.....i'm fighting the android udev which is overwriting my symlinks..
see you!

i got it!
my initial target was to remove devices created by ueventd and replace them with symlink to loop devices.
but android respawn ueventd and replaces my symlinks...
i tried to start the android ueventd, leave it running, and replace the /sbin/ueventd with a infinite sleep static program
but android dont' start at all..i can't even access via adb.
so, the "final" solution is to edit the /fstab.$hardware, which should be in any andoird boot image ( right ? ).
please feel free to suggest any other way to hack the mount process.
you can find the sources here: https://github.com/tux-mind/tf201-dev/tree/master/android_chooser
the program read the paths from kernel cmdline.
the syntax is that:
Code:
newandroid=blkdev:initrd_path:fstab_path
where
blkdev is the linux name of the blockdevice containing the next args ( e.g. /dev/mmcblk0p8 )
initrd_path is the path on the previous blockdevice of the android initrd ( gzipped or not )
fstab_path is the path on the previous blockdevice of the fstab file
the fstab file have this syntax:
Code:
/android/mountpoint /path/to/image/file
where
/android/mountpoint is the android mountpoint to overwrite ( e.g. /system )
/path/to/image/file is the path to the filesystem image file ( on blkdev ) ( e.g. /boot/unrooted.img )
i don't make any documentation until i will be sure that there is no better way to do this.
thanks in advance for your testing
ah, some other useful info.
because we are in testing the program write a log file with some debug info in the root of your blkdev.
so you will find /android_chooser.log on your blkdev with these info in case of errors.
tux_mind

Please
dtrail1 said:
Really great idea! As it support other devices I can throw in my kernel which is a kexec one for the Motorola RAZR, because of our locked bootloader. The question is: how different are the methods to use kexec?
M.o.t.o.r.o.l.a.R.a.z.r - JBX-Kernel 0.5a - Tapatalk4
Click to expand...
Click to collapse
Dtrail could you explain me kexec and its components required for loading new kernel because my device(electrify 2) is similar to droid razr. Using bmm kexec is boot able because I had checked by flashing droid razr's kernel which gave a boot loop.
I would be pleased and thankful to you if you help me.

[KERNEL] dagkernel 0.01 (for stock/stock based ROMs)

Hi!
I picked up a G3 about a month ago, great device! Why'd it take me so long? I'm broke as a joke and married, so I had to wait until it was almost free with a 2yr contract @ AT&T, and for permission from wifey, since her phone is graciously used as my guinea pig
I've been tinkering with it since then, decided I liked the stock experience pretty well (with GEL, root, debloat, etc.), but I decided I wanted a bit more features than the available kernels offer. I also noted some of the overclocking code and scripts could use a bit of re-tooling to lower the number of CPU cycles eaten and give better responsiveness.
Main thing that bugged me was that LG hadn't yet released 21q source, so I started harassing them for it. Finally got the email back I was waiting for telling me it was posted
So, this is my first release, just a simple boot.img you'd have to flash yourself from adb. I'm putting together a fresh build environment since my dev laptop was stolen, it's all new again!
Changes vs. stock (v21q)
Code:
ro.debuggable=1
ro.adb.secure=0
ro.secure=0
ro.allow.mock.location=1
init.d support
Changes planned:
Code:
Over/underclocking for CPU,GPU,other clocks I might find interesting to tinker with, and using new optimized code
Over/undervoltage of the same as above
Kernel modules with nifty things like cifs support I might find useful
Package up a pretty installer script
Support for Whetstone on-the-fly sharpening control https://play.google.com/store/apps/details?id=savoca.codefi.re.whetstone
Request other stuff and i'll consider it!
How to flash:
Code:
unzip the .img file, copy to your external sd card (or internal if you like, but change the path accordingly)
open adb, get a root shell (adb shell, su) - or use a terminal emulator on device for same
enter into shell: dd if=/storage/external_SD/newboot.img of=/dev/block/platform/msm_sdcc.1/by-name/boot
reboot, done!
fin

Hi, this post is for me. Thanks!

So this is a Lollipop kernel then correct? What features does it have? Thanks in advance.

does this kernel set selinux mode to permissive by default?

joho5 said:
does this kernel set selinux mode to permissive by default?
Click to expand...
Click to collapse
Yes

Why not just make this a flashable zip....?

4/20/2017 [] 7.1.1 UPDATE [] LG G5 (msm 8996) [] CPU, VM, RAM, IO "Tune"

ORIGINAL THREAD HERE: https://forum.xda-developers.com/axon-7/development/2-15-2017-axon-7-msm-8996-cpu-vm-ram-t3557392
This mod was originally created for the Axon 7, but due to several requests, I've modified a version for the G5, please see below, and post questions or comments in the original thread above. Please state you are a G5 user if you have feedback in that thread, to consolidate user feedback and speed up response time.
Custom tuning for a device is always a necessity. "Canned" settings will get you by, but they are certainly never optimized for a specific device. In fact, Linux typically takes a general approach to find harmonic balance in default settings that will, for the most part, work in an acceptable manner for just about any device. There are a lot of resources available on this device, so we should utilize it in a manner appropriate to squeeze out as much battery life and performance as possible without sacrificing much of those outputs, don't you think? This is going to fix that for you.
Here is what is required of you before you begin:
1. Must be rooted
2. Must have the G5 OR a device running the Snapdragon 820, as this modification is not so much device specific, but hardware specific. The important aspect being the snapdragon 820 and the RAM disk size.
3. Must have write protection disabled. If the G5 requires write protection to be disabled, see the code and instruction below:
Using adb shell:
Code:
adb reboot disemmcwp
Using Linux terminal (from your phone, for example):
Code:
reboot disemmcwp
Let's begin.
Getting right to it, here's what I've done:
- modified parameters of the interactive governor, and quite extensively at that (search some of my threads if you want a little bit of a breakdown of the general approach I take)
- reconfigured input_boost parameters
- reconfigured vm parameters (again, the device has a lot of RAM resource, this will utilize it and give you a far better user experience. Basically, I've adjusted dirty_ratio, dirty_background_ratio, swappiness, and other parameters of the virtual machine.)
- disabled zRAM for 6 GB variants (RAM compression, again, not needed on this device really, this mod will save you CPU cycles and power) this will not apply to G5 users, you will still have zRAM enabled.
- remapped minfree parameters for LMK (low memory killer) again only for 6 GB variants
- Tuned CFQ scheduler for flash storage devices
- Tuned "core_ctl" module (needs kernel support, I recommend freeza's latest version of BeastMode. For those wondering, yes, you can still use this mod with the stock kernel. It won't break anything.) again this will only apply to devices that support core_ctl at the kernel.
In a nutshell, that's what we're looking at here. I can guarantee you this will have a significantly positive impact on your device. Turbo time, homies.
How to install????
Easy. First, the file we are replacing is found in /system/etc... it is the "init.qcom.post_boot.sh" file - this file is basically shell scripts, which are applied at boot via this particular shell file.
All you have to do is download the file to your device, open up a file explorer (must have root capability), navigate to the /system/etc folder with said file explorer, mount your /system as RW (read write), delete your stock "init.qcom.post_boot.sh" file, and replace it with mine.
After you've successfully done this, change the new file's permissions to rw-r--r-- (0644), and then reboot!
Or, if you are brave, you can do it manually via a terminal app and get your fingers wet... if you choose to do that, see below:
Make sure the file is located on the root of your internal sdcard in /sdcard, open your terminal app (again, must have root) and type the following commands, hitting enter after each one (be careful to pay attention to the spacing).
Code:
su
Code:
cd /
Code:
mount -o remount,rw /system
Code:
cd /system/etc
Code:
rm init.qcom.post_boot.sh
Code:
cd /sdcard
Code:
mv init.qcom.post_boot.sh /system/etc
Code:
chmod 0644 /system/etc/init.qcom.post_boot.sh
I don't want credit, don't need you to give or offer donations, this is purely for the community in the spirit of Linux ideology. All I ask is for you to hit the thanks button :good:
That's pretty much it, guys. Enjoy!
DOWNLOAD:

Is this a new kernel?
Regards
Nathan
Sent from my LG-H850 using XDA Premium HD app

@warBeard_actual
Here :good: :fingers-crossed:

onestyle007 said:
@warBeard_actual
Here :good: :fingers-crossed:
Click to expand...
Click to collapse
Got it man, working on it now. I should have it up soon.

OP updated... Enjoy guys!
Instructions on how to install are in the OP, post your results here

warBeard_actual said:
OP updated... Enjoy guys!
Instructions on how to install are in the OP, post your results here
Click to expand...
Click to collapse
Question,does that matter for your results if I'm using an other governor,cause I'm currently on alucard?? Stock rom but a custom kernel (Asgard for g5 to be exact)

onestyle007 said:
Questions,does that matter for your results if I'm using an other governor,cause I'm currently on alucard?? Stock rom but a custom kernel (Asgard for g5 to be exact)
Click to expand...
Click to collapse
You will notice minimal to no difference if you are using another governor.

Any pro can do a flashable zip?

Any n00b can copy and paste

Will it work on Android 6?

I don't know it's placebo or not but after replacing the file I have now a better GPS fix and accuracy I am on the H850 so thanks on the OP

yes accurancy gps, not lag boot, very smooth. thanks!!!!!!!!!!!

warBeard_actual said:
OP updated... Enjoy guys!
Instructions on how to install are in the OP, post your results here
Click to expand...
Click to collapse
Okay,last night after I've replaced the file, changed to interactive gov,0.2% lost during the night with wifi and mobile data off here is my current stats. Was a bit surprised though and I'm not sure if it's a bug in reading . But hey that's what it shows.

Rhadamanthis said:
yes accurancy gps, not lag boot, very smooth. thanks!!!!!!!!!!!
Click to expand...
Click to collapse
Same for me, let see if the battery will be better too...

Does this only work on LG Stock?

Hi,thanks for mod,great mod running in Nougat Fulmix rom?

OTOGY2002 said:
Hi,thanks for mod,great mod running in Nougat Fulmix rom?
Click to expand...
Click to collapse
Ues

How to mount System as R/W? When I set permission I get error evice is busy

Worked like a charm using Fulmics Rom 2.0.
Hint for some who have issues with mounting RW: Use FX file explorer for this. Works just fine.
Will monitor and report how it works.

My Problem. I go to /system/etc and I can´t find this file. I´m on Root with FX file Manager. What am I doing wrong?